Block and Piston Inspection

Remove the crankshaft and the pistons (see CRANKSHAFT AND PISTON REMOVAL ).
Check the piston for distortion or cracks.
Measure the piston diameter (A) at a point 16 mm (0.6 in.) from the bottom of the skirt.
Piston Diameter

Standard (New): 72.980-72.990 mm (2.8732-2.8736 in.)

Service Limit: 72.97 mm (2.8728 in.)

Oversize Piston Diameter

0.25: 73.230-73.240 mm (2.88307-2.88346 in.)

Fig 1: Measuring Piston Diameter
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Measure wear and taper in direction Y at three levels in each cylinder as shown below. If measurements in any cylinder are beyond the Oversize Bore Service Limit, replace the engine block. If the engine block is to be rebored, refer to step 7 after reboring.
Cylinder Bore Size

Standard (New): 73.000-73.015 mm (2.8740-2.8746 in.)

Service Limit: 73.065 mm (2.8766 in.)

Oversize

0.25: 73.250-73.265 mm (2.8839-2.8844 in.)

Reboring limit: 0.25 mm (0.01 in.) max.

Bore Taper

Limit: (Difference between first and third measurement) 0.05 mm (0.002 in.)

Fig 2: Measuring Wear & Taper In Direction Y
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Scored or scratched cylinder bores must be honed (see CYLINDER BORE HONING ).
Check the top of the engine block for warpage. Measure along the edges and across the center as shown below.
Engine Block Warpage

Standard (New): 0.07 mm (0.003 in.) max.

Service Limit: 0.10 mm (0.004 in.)

Fig 3: Checking Top Of Engine Block For Warpage
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Calculate the difference between the cylinder bore diameter and the piston diameter. If the clearance is near or exceeds the service limit, inspect the piston and engine block for excessive wear.
Piston-to-Cylinder Clearance

Standard (New): 0.010-0.035 mm (0.0004-0.0014 in.)

Service Limit: 0.05 mm (0.002 in.)

Fig 4: Identifying Piston-To-Cylinder Clearance
Courtesy of AMERICAN HONDA MOTOR CO., INC.